First, those who are leaving the church for Protestant churches are more interested in spiritual nourishment than doctrinal issues. Tinkering with the wording of the creed at Mass is not going to help. No one except the Vatican and the bishops cares whether Jesus is “one in being” with the Father or “consubstantial” with the Father. That the hierarchy thinks this is important shows how out of it they are.
While the hierarchy worries about literal translations of the Latin text, people are longing for liturgies that touch the heart and emotions. More creativity with the liturgy is needed, and that means more flexibility must be allowed. If you build it, they will come; if you do not, they will find it elsewhere. The changes that will go into effect this Advent will make matters worse, not better.
Second, thanks to Pope Pius XII, Catholic scripture scholars have had decades to produce the best thinking on scripture in the world. That Catholics are leaving to join evangelical churches because of the church teaching on the Bible is a disgrace. Too few homilists explain the scriptures to their people. Few Catholics read the Bible.
The church needs a massive Bible education program. The church needs to acknowledge that understanding the Bible is more important than memorizing the catechism. If we could get Catholics to read the Sunday scripture readings each week before they come to Mass, it would be revolutionary. If you do not read and pray the scriptures, you are not an adult Christian. Catholics who become evangelicals understand this.
Finally, the Pew data shows that two-thirds of Catholics who become Protestants do so before they reach the age of 24. The church must make a preferential option for teenagers and young adults or it will continue to bleed. Programs and liturgies that cater to their needs must take precedence over the complaints of fuddy-duddies and rubrical purists.
Current religious education programs and teen groups appear to have little effect on keeping these folks Catholic, according to the Pew data, although those who attend a Catholic high school do appear to stay at a higher rate. More research is needed to find out what works and what does not.
Interesting, though I think the old saying that “the grass is always greener on the other side of the hill” applies here. For example, not many Protestants, including evangelicals, read the Bible either. And is the “make it up as you go along” approach of some Protestant “free” churches really better than a fixed, traditional liturgy? I doubt it very much. As for teenagers and youth, many Protestant churches have great difficulty retaining them too.